In many machining applications, most typically grinding the surfaces of the cams and journals of camshafts and crankshafts, the nonstraight workpiece is rotated about a normally horizontal axis while a grinding tool is urged against the surface to be ground. Since the cams and journals are offset from the axis about which the nonstraight workpiece is rotated, it is necessary for the grinding tool to reciprocate radially synchronously as the workpiece rotates so as to stay in contact with the surface being machined. The workpiece is chucked between a headstock and tailstock mounted on a bed that is typically stepped parallel to the axis to bring the surfaces to be ground one after another into alignment with the grinder.
In German utility model 92 18 553 this is accomplished by mounting the grinding tool on a slide that shifts on horizontal rails underneath and slightly to the side of the workpiece in a direction perpendicular to a vertical plane including the workpiece rotation axis. An appropriate actuator slides the grinding tool back and forth as the workpiece rotates. The workpiece and/or the tool slide can be shifted parallel to the axis so that the tool can be brought into engagement with the axially spaced surfaces of the workpiece.
The grinding tool is thus subjected to fouling from the cutting oil and coolant that is applied to the workpiece, and that flies off radially during the machining operation. In addition particles from the machining operation can get into the slide rails, leading to premature wear. Furthermore the relatively massive slide arrangement necessitates a fairly powerful actuator to move the grinding tool synchronously with the rotating workpiece.